A thin client system has attracted attention in recent years because of heightened sense of crisis concerning information leakage and growing concerns about importance of a reduction in cost involved in management of a business system.
A terminal device used in a thin client system, i.e., a thin client terminal is a terminal device provided only with minimum required functions (e.g., OS with limited functions, screen transfer application, BIOS (Basic Input/output System)) and is configured to utilize applications and business data stored in a server. Thus, the thin client terminal does not have a storage such as an HDD (Hard Disk Drive). If the thin client terminal has a storage, data created by a user, such as business data, is not at all stored in the storage.
Therefore, even if the thin client terminal has been stolen, information is not leaked outside from the stolen thin client terminal. Further, an OS or applications that the thin client terminals use can be managed on the server side, allowing setting for the thin client terminals to be collectively made. Accordingly, it is possible to promptly apply a patch to the OS or application in the individual thin clients, allowing an administrator to perform effective management for operation of the terminal devices.
There exist several types of thin client systems. For example, there is known a network boot thin client system in which a thin client terminal downloads an OS or application from a server and executes the downloaded OS or application on the terminal.
Hereinafter, with reference to FIG. 17, the network boot thin client system will be described.
A thin client terminal 1A which is a terminal device having no storage accesses, at its start-up time, an operation management server 3A that manages operation of the thin client terminal through a network 2. Then, the thin client terminal 1A downloads OS data required for the terminal 1A to operate from the operation management server 3A and boots it. After that, when executing an application, the thin client terminal 1A downloads the application and a library required for the execution of the application from the operation management server 3A.
The network boot thin client system is advantageous in the following points: it involves low facility cost; it exhibits excellent performance at the execution time of a job; and it provides easy access to peripheral devices.
However, the thin client terminal cannot be booted in a mobile environment that the thin client terminal is not connected to a network at its power-on time.
Even if a thin client terminal 1B in the mobile time uses a public network 4 with a narrow bandwidth to access a network and can be booted, it is necessary for the thin client terminal 1B to download an application and a large number of libraries required for execution of the application from a file server before executing the application. Thus, under a situation where it is difficult to perform broadband communication, the network boot thin client system is difficult to use.
Under the circumstance, there has been proposed a technique in which an OS and an application have previously been stored in a read-only medium, such as a CD-ROM or USB-ROM and the thin client terminal boots the OS from the medium and loads an execution image of the application.
In this technique, the thin client terminal does not use a network for booting an OS having a large size or loading an application having a large size but boots the OS or executes the application from the read-only medium, allowing the thin client terminal to easily boot the OS or load the application.
Meanwhile, business data that individual users use are stored in an operation management server, and the thin client terminal uses remote access dial-up connection or wireless LAN to access the business data. Thus, the business data are not stored in the individual thin client terminal, allowing prevention of information leakage.
In this case, however, a user of the thin client terminal always needs to carry a medium storing the OS or application and, therefore, there is a possibility of damage or loss of the medium. Further, the medium needs to be created and delivered every time the OS or application is updated, increasing operation cost. Further, when a CD-ROM is used for the delivery of the OS or application, a component for driving the CD-ROM needs to be provided and, accordingly, the rate of occurrence of failure increases, resulting in an increase in maintenance cost.
In order to cope with this, a method can be considered in which the OS or execution image of the application is stored in a CF (Compact Flash) incorporated in the thin client terminal or a writable non-volatile memory device such as a USB memory and the operation management server remotely manages the thin client terminal.
However, allowing data to be written into such a medium allows a user to store important data in the thin, client terminal, causing a risk of information leakage.
There is known a technique, although it has not been designed for the network boot thin client, that realizes a mechanism in which the OS or application provided in the terminal is managed from outside the terminal. In this technique, an operation management server has its inside a simple virtual appliance. A user of a terminal cannot access (operate) the virtual appliance but only an administrator operating an external IT console can use the virtual appliance. An OS or application provided in the terminal can be updated through the IT console. However, a management function itself is provided in the terminal, there is a risk that the management function in the terminal may be falsificated.
As a prior art relating to the present invention, there is known a method for configuring network settings of a thin client using a computer-readable portable storage medium (refer to, e.g., Japanese Laid-open Patent Publication No. 2005-216292).
As described above, in the case where the thin client terminal is used in the mobile environment, when importance is attached to security against information leakage, operation management cost is increased, while when importance is attached to easiness of the operation management, a risk of the information leakage is increased.